Measuring and decomposing the impact new rapid transit lines have on properties adjacent to existing rapid transit infrastructure

The transit capitalization literature documents how new rapid transit stations affect nearby property values, but largely ignores the spillover effects on properties already adjacent to the existing network: when a new line opens, it both improves connectivity for existing station-area residents (a network effect) and expands the supply of transit-oriented housing, eroding the scarcity premium of existing station-adjacent properties (a substitution effect), leaving the aggregate impact theoretically ambiguous. We study this question using two case studies (the Canada Line in Vancouver and the Expo Line in Los Angeles), constructing pre- and post-opening accessibility measures from historical GTFS and OpenStreetMap data via OpenTripPlanner and embedding these in a Two-Way Fixed Effects Difference-in-Differences design, with property-level BC Assessment transaction data (hedonic and repeat sales) for Vancouver and Zillow Home Value Index data at the ZIP code level for Los Angeles. In Vancouver, the repeat sales specification finds that properties within 1 km of pre-existing stations appreciated by 4.2–8.5% relative to the donut control group following the Canada Line opening, with network effects (6–8%) substantially outweighing substitution effects (under 1%); in Los Angeles, the DiD estimate is a positive but statistically insignificant 2.0%, stable across accessibility specifications, and in neither city do we find evidence that the new line reduced values near existing stations. These findings suggest that incremental transit expansion generates genuine new value throughout the network rather than simply redistributing a fixed premium, implying that value capture mechanisms tied to new transit corridors likely underestimate the full geographic footprint of transit benefits.